The statute, by its terms, mandates only maximum and minimum sentences: A person convicted of possession with intent to distribute 5 grams or more of crack cocaine must be sentenced to a minimum of 5 years and the maximum term is 40 years. A person with 50 grams or more of crack cocaine must be sentenced to a minimum of 10 years and the maximum term is life. The statute says nothing about the appropriate sentences within these brackets, and we decline to read any implicit directive into that congressional silence.

In formulating Guidelines ranges for crack cocaine offenses, as we earlier noted, the Commission looked to the mandatory minimum sentences set in the 1986 Act, and did not take account of “empirical data and national experience.” See Pruitt, 502 F. 3d, at 1171 (McConnell, J., concurring). Indeed, the Commission itself has reported that the crack/powder disparity produces disproportionately harsh sanctions, i.e., sentences for crack cocaine offenses “greater than necessary” in light of the purposes of sentencing set forth in §3553(a). See supra, at 8–9. Given all this, it would not be an abuse of discretion for a district court to conclude when sentencing a particular defendant that the crack/powder disparity yields a sentence “greater than necessary” to achieve §3553(a)’s purposes, even in a mine-run case.